Digital Fractional Order Differentiator/integrator - IIR type

A new general IIR digital fractional order differentiator/integrator based on continued fraction expansion of weighted operator which is mixed scheme of the trapezoidal (Tustin) rule and the backward difference (Euler) rule.

See also here
http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=3518&objectType=FILE
More information is here
http://www.csois.usu.edu/people/yqchen/dd/index.html
and here
http://mechatronics.ece.usu.edu/foc/